Well that would be stealing, the same as if you walked out of the room during a commercial.

I'm sure there's a way around it but is it really worth the effort? Anything important is going to be reported by multiple sources citing the original source in minutes. Niche information from a specific publication will be widely circulated among the various online communities that focus on that niche. The only people effected will be the ones who only have a casual interest -- the ones least likely to sign-up for free access much less pay. Once people get a taste for unlimited free information it's almost impossible to go back.

> Or a Firefox extension does this for me?

Isn't there already a bugmenot.com FF extension?

Might be done by IP.